The overall objective of this proposal is to elucidate the cellular, biochemical and molecular mechanisms involved in modulation of T-cell function by catecholamines. Studies are designed to investigate the immunologic consequences of stimulating the beta 2 adrenergic receptor (BAR) on T-cells and their subsets with triggering through the T-cell receptor (TCR). This dual signaling will be achieved by stimulating resting human T-cells with the beta adrenergic agonist isoproterenol (ISO) and the mitogen anti-T3 monoclonal antibody (mab) or phytohemagglutinin (PHA). The experiments are proposed to determine the temporal immunomodulatory effect of this dual receptor interaction on transit of T-cells through the cell cycle from G(O) - G(l) and from G(1) - S phase as reflected by cell cycle analyses, interleukin 2 (IL-2) production and expression of the IL-2 receptor (IL-2R). Because T-cells also require signals from accessory cells to become fully activated, the effects of BAR stimulation on monocytes will be determined. These experiments including assessing the effects of ISO on the ability of monocytes to produce cytokines and express "Ia" antigen. A further delineation of the characteristics of the synergistic rise in cAMP levels in T-cells after stimulation with ISO and anti-T3 mAb or PHA are proposed. Experiments are presented to identify those elements of the cAMP second messenger system which are modulated via dual stimulation of the BAR and TCR. These include modulation of the BAR, G-proteins, adenylate cyclase and cAMP phosphodiesterase activity. Concurrently, we also will examine how second messengers (Ca2+, protein kinase C) emanating from TCR stimulation are capable of facilitating cAMP accumulation in T-cells. The final set of experiments will determine the effects of dual receptor interactions on a variety of transmembrane signals resulting from phosphotidylinositol cycle turnover and oncogene expression associated with the ability of appropriately stimulated T-cells to enter and transit the cell cycle from G(O) - G(1). Experiments also are presented to evaluate those intracellular events linked with continued progression from G(1) to the S phase of the proliferative cycle.